Obesity is a disease caused by a metabolic error, in which excessive energy in a body is converted into fat and the fat is excessively accumulated in adipose tissue, thereby abnormally increasing body fat. A factor causing obesity is largely divided into a genetic factor and an environmental factor (such as, a meat-oriented dietary life, a reduction of quantity of motion, etc.). Besides, there are other factors such as a neuroendocrine factor, a drug factor, etc.
Obesity, which has been already defined as a disease in 1996 by WHO, is one of the most rapidly increasing chronic diseases these days all over the world, and is a main dangerous factor causing “adult diseases” such as diabetes, hyperlipidemia, atherosclerosis, a cardiovascular system disease, etc. As direct and indirect expenses according to a sudden increase of obesity population have been increased all over the world, markets related to obesity and adult diseases have rapidly grown, thereby resulting in rapidly increased tendency of the extent of loss.
A target for treating such obesity includes controls of appetite, fat metabolism, adipocyte differentiation, fat absorption, energy metabolism, etc., and research focusing on the controls has been actively carried out. At present, there are two drugs for treating obesity, of which long term use is approved by the U.S. FDA, including sibutramine (REDUCTIL) having an action mechanism of suppressing reabsorption of norepinephrine and serotonin, and orlistat (XENICAL) having an effect by suppressing lipase secreted from the pancreas and digestive system. Sibutramine was originally developed as an antidepressant, but at present is used as an obesity therapeutic agent due to its excellent anti-obesity effect. According to recently reported research results, the use of sibutramine for at least one year or more resulted in a reduction of body weight by more than 4.3 kg, or 4.5%, as compared to a placebo group. However, the use of sibutramine gives rise to side effects, such as an increase in blood pressure, insomnia, xerostomia, vertigo, etc., and also, sibutramine has a disadvantage in that it cannot be used for a patient having a cardiovascular disease such as hypertension. Orlistat reduces absorption of fat included in an ingested food by about 30% by suppressing an action of lipase secreted from the pancreas and digestive system. According to recently reported research results, administration of orlistat for one year resulted in a reduction of body weight by 2.7 kg, or 2.9%, as compared to a placebo group. However, the use of orlistat gives rise to side effects, such as diarrhea, fatty stool, fecal incontinence, etc., and in the case of people ingesting a small amount of fat (such as Koreans), unlike Westerners, the effect of the drug is not significant. Due to limitations of drugs up to now developed in order to treat obesity, it is inevitably required to develop a drug having a new action mechanism, which has a high anti-obesity effect and gives rise to reduced side effects.
In using natural drugs that have been used for traditional medicine, there is no need to be deeply concerned over the toxicity caused by a developed drug because the natural drugs have been used for ages, and also there is very high possibility of finding a new active ingredient based on the demonstrated efficacy of a drug.
Therefore, the inventors of the present invention have tried to find a drug for suppressing adipocyte differentiation in order to find a more efficient obesity treating/preventing method using a natural drug of high economical efficiency and reduced side effects, and as a result, have completed the present invention by demonstrating that an extract of lysimachiae foenum-graeci herba (which is a medicinal plant) has a high effect on obesity prevention/treatment.